I've been banging my head against a wall for a while now on this issue.  Here's the setup on my rig:

M600 Pro
Ronin-MX Gimbal
Sony A7Rii
RUNCAM FPV Flight Cam
Dual Pilot with Master / Slave RCs
Crystal Sky Dispalys
ALL FIRMWARE UPDATED

Upon initial power up both remotes come online as expected.  I set the MASTER to view the RUNCAM via "HDMI / AV" selection under HD settings.  I set the SLAVE to the Sony via "HDMI/AV" selection under HD settings.  Got great video on both displays.  Within only a few minutes on the ground, the slave video display goes gray and the video no longer updates.  I can still control the gimbal but nothing on video.  I can swap back to my RUNCAM on the slave and then back to HDMI and I'll get the image transmission again but only for a few mins and then it goes gray (by going gray... the last image is still there like it froze but all color is removed).  According to DJI, the gimbal / camera shutter control runs between master and slave RCs but the video transmission is from the M600.  I cannot for the life of me figure out what's going on or why.  I've heard of people having this issue with the Inspire 2 but my I2 has never even had an issue like this... but this M600... ready to shoot it.

I've reset both RCs... relinked the master... nothing seems to fix it.  I've played with the percentages HDMI / AV... none seem to fix this.

Can DJI offer a solution to this?  From what I've read it's an issue that's been going on for a while.

THanks,

-Andy

Sorry to read on your frustration. Check first with one remote and see if the issue is ongoing. You need to determine if this is a remote issue or camera related. Also consider whether the camera is taking videos that you are not seeing or if the camera itself is at fault. Send me a personal message if you like with the answer.

DJI-Mark Posted at 2018-3-16 10:51
Sorry to read on your frustration. Check first with one remote and see if the issue is ongoing. You need to determine if this is a remote issue or camera related. Also consider whether the camera is taking videos that you are not seeing or if the camera itself is at fault. Send me a personal message if you like with the answer.

It does this with any camera we fly.  We flew today and would have to have the slave operator switch to AV for a second and then back to HDMI to regain the live camera feed.  I can swap master / slave remotes on aircraft and the former slave (now master) will hold live feed for duration of flight and the former master (now slave) has the same issue.  We rechecked all cabling on M600 (which is a pain) and verified every cable's condition on a scope to make sure we didn't have a rogue cable.

This issue isn't unusual from a google search and it's frustrating bc it makes dual piloting hard and slows down workflow.

So,... what I'm thinking about doing is this but need to know if I can do it.  I want to purchase a sep LB2 air unit and remote and power it from the aircraft but wire the gimbal and camera feed to it.  This would allow me to fly dedicated on one remote and have a dedicated remote that can be master on the 2nd LB2 and get the same long range transmission.  Right now I'd rather spend $1k and be done with this issue and look more professional on sets than be killing time (which is money and battery life) having to pause and reset.

The camera is recording but when you are tracking something with gimbal movement and then the slave feed freezes and won't recover until we switch from HDMI to AV and back to HDMI... we lose our shot as the drone is in motion along with our target.

Thanks for the help.  Let me know if the 2nd LB2 setup would work.

-Andy